Apparatus for manufacturing cellulose.



No. 659,3l3. Pafented Oct. 9, I900. E. momznun.

APPARATUS FOR MANUFACTURING CELLULOSE.

(Application filed Feb. 7, 1900.

(No Modal.)

Witnsses: Inventor; M y; MMW Jf/M 0 {m5 NORRIS PETERS o0. PuoYoLm. wAsnmumN, u. c,

UNITED STATES PATENT OFFICE.

EINAR MORTERUD, OF KONGA, SWEDEN.

APPARATUS FOR MANUFACTURING CELLULOSE.

SPECIFICATION forming part of Letters Patent No. 659,313, datedOctober 9, 1900. Application filed February 7, 1900. Serial No. 4,382. (No model.)

To all whom it may concern.-

Be it known that I, EINAR MORTERUD, a citizen of the Kingdom of Norway, residing at Kouga, Sweden, have invented certain new and useful Improvements in Apparatusfor the Manufacture of Cellulose; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to the well-known processes whereby wood and like materials are converted into cellulose by cooking them in an acid or alkaline solution. It is known by every one familiar with this manufacture that the cooking process takes a very long time and that this is partly due to the fact that the solution so very slowly enters into the pores of the wood. For this reason the manufacture of cellulose is a very expensive process, because the plant of digest-ers has to be very large for a comparatively-small prod uction. It has been proposed to overcome this difficulty by treating the wood,"before it is cooked, in a special tank, in which the solution is forced into the pores of the wood by way of pressure. In this manner, it is true, the cooking process itself is shortened; but the expensiveness'of the plant is correspondingly increased, because a double set of digesters is necessary, and therefore no real useful effect is obtained by this previous impregnating process. I have found, however, that an advantageous result may be obtained without employing any special impregnating pressure-tank. According to my invention I obtain a valuable reduction in the time necessary for carrying out the cooking process and also a reduction in the cost of the plant as compared with its effective work simply by employing a large tank in which the wood to be treated and the acid or alkaline solutionare stored instead of storing these materials separately, as usual.

My invention will now be described with reference to annexed drawing, which shows the general arrangement of my apparatus.

or represents a storage-tank, and b a digester, (for the sulfite process,) the latter being connected with the tank through the pipe 0. The drawing shows one tank and one digester; but it is to be understood that one tank is to be used for a set of digesters, it being given a volume as large as two or three digesters. The pipe 0 is provided with the necessary valves, as shown, for purposes easily understood. From the upper part of the boiler 11 is carried another pipe 6 to the tank a. In this pipe is arranged a pump p-for instance, a centrifugal pump. The pipe 6 is provided with a strainers. A third pipe g, provided with valves, is also carried from the top of the boiler to the bottom part of the tank. The tank has ahopper-valve at o and a pipe Z leading to the acid apparatus. The pipes 15 and u are pipes leading from a steamgenerator into the tank and into the pipe 0.

The apparatus may be usedin the following manner, it being supposed that the boiler b has just been filled with wood and solution from the tank a, through pipe 0, the stock of wood and solutionin the tank a will thereby sink down and more wood and solution may be introduced into the tank. Such filling, however, can be carried on all the time, as material is produced. If through the filling of the digesterb too much solution is brought over from the tank to the digester, the superfluous solution may be taken back to the tank through pipe e by means of the pump 19, the strainer s prohibiting wood to be taken along with the solution. If the filling of the digester through the pipe 0 is going on too slowly, it may be accelerated by way of a steam-jet or a pump arranged in the pipe 0 through the pipe at. During the cooking process and after the finish of thecooking gases from the digester may be driven through the pipe 9 to the bottom of the tank a, in which it is absorbed by the solution. This solution will thereby be heated, and gas not absorbed in the bottom part of the digester will rise to the top, where it finds a colder solution. The not-absorbed gas may escape through the pipe I to the acid apparatus. Steam may be led to the tank through pipet if a temperature of its contentsabove that obtained by the gas is wanted. As will be seen, I obtain in this manner a very effective utilization of the gas escaping from the digester and the wood is impregnated prepara tory to the introduction in the digester by very inexpensive means and in a very economical manner. By working in this man nerI obtain a finer and more uniform product, as the wood is not exposed to the high temperature and great pressure till it has been completely soaked by the solution. In this manner it has been found that less solution and steam are required for a certain quantity of cellulose, and thereby the general costs are lessened.

hat I claim is 1. The combination of digesters, a common storage-tank for containing raw material and solution for treating the raw material, pipes connecting the storage-tankwith each digester for supplying the said solution and raw material to the digesters, and valves on the pipes.

2. The combination of a digester, a storagetank for containing raw material and solution for treating the raw material, a pipe connecting the bottom of the storage-tank with the digester for supplying said solution and raw material to the digester, and valves on the said pipe.

3. The combination of a digester, a storagetank for containing raw material and solution for treating the raw material, a pipe connecting the bottom of the storage-tank with the bottom of the digester, means forcing the solution and raw material through said pipe into the digester, and valves on said pipe.

t. The combination of a digester, a storagetank for containing raw material and solution for treating the raw material, a pipe con necting the bottom of the storage-tank with the bottom of the digester, a steam-jet for forcing solution and raw material through said pipe into the digester, and valves on said pipe.

5. The combination of a digester, a storagetank for containing raw material and solution for treating the raw material, a pipe con necting the bottom of the storage-tank with the bottom of the digester, means on said pipe for forcing the solution and raw material into the digester, a pipe connecting the upper part of the digester with the lower part of the storagetank, and valves on the said pipes.

6. The combination of adigester, astoragetank for containing raw material and solution for treating the raw material, a pipe connecting the bottom of the storage-tank with the bottom of the digester, means on said pipe forcing the solution and raw material into the digester, a pipe connecting the upper part of the digester with the lower part of the storage-tank, valves on the said pipes, a pipe connecting the intermediate part of the digester with the storage-tank, and means on said pipe for forcing the solution from the digester in to the storage-tank.

7. The combination with a cellulose-digester of a storage-tank for raw material and solution for treating the raw' material, said tank having at its top an opening for the introduction of raw material and being at its bottom provided with pipes leading to the digester, through which gas may be carried back from the boiler to the storage-tank substantially as described.

In witness whereof I have hereunto set my hand in presence of two Witnesses.

EINAR MORTERUD.

WVitnesses:

HENRY BORDEWIOH, JOHN P. BoRDEWIcH. 

